The present invention relates to a rod-shaped multi-layer tampon for medical or hygienic purposes and to a method for its manufacture.
Rod-shaped tampons for hygienic purposes, particularly for feminine hygiene purposes, are known. These tampons generally comprise a strand of wound cotton compacted by radial pressure. The strand of cotton usually comprises a mixture of cotton and cellulose to which swellable substances may have been added in order to increase its fluid absorption capacity. At one end, the rod-shaped product, which is rather rigid after the pressing process, has a retrieval string which serves to remove the tampon from the body cavity after use.
In addition to the mentioned hygienic tampons, other types of tampons are known which primarily serve medical purposes. They are also introduced into a body cavity but their principal purpose there is not to absorb bodily fluids, for example, menstrual fluids, but rather to discharge active substances which serve to treat the body cavity. Such a tampon is disclosed, for example, in Federal Republic of Germany Patent No. 3,122,954. This tampon is made of foamed polyvinyl alcohol acetal containing medications for use in various fields of therapeutic medicine.
One of the main problems in tampons intended to discharge active substances into the body cavity is that these active substances must be discharged slowly over as long as possible a period of time, without the reverse process of the absorption of fluids from the body cavity interfering with the release of these active substances. It has been found that this cannot be satisfactorily accomplished with tampons made of cellulose or other fibers or of open-pored plastic foams, such as foamed polyurethane, polyvinyl alcohol, cellulose or rubber, due to their absorptive action.
Annular sponges impregnated with contraceptive agents are known. These sponges are made of native collagen in the form of fibrous proteins which are introduced into the vaginal cavity as required. Sponge rings of this type are disclosed, for example, in U.S. Pat. No. 4,274,410. The material is soft-elastic so that it is not suitable for the production of tampons or medical tampons. However, it is well suited as a carrier for the mentioned active substances and has been found satisfactory in this respect.